We compute theoretical predictions for the production of a $W$ boson in association with a bottom-quark pair at hadron colliders at next-to-next-to-leading order (NNLO) in QCD, including the leptonic decay of the $W$ boson, while treating the bottom quark as massless. This calculation constitutes the very first $2\to 3$ process with a massive external particle to be studied at such a perturbative order. We derive an analytic expression for the required two-loop five-particle amplitudes in the leading color approximation employing finite-field methods. Numerical results for the cross section and differential distributions are presented for the Large Hadron Collider at $\sqrt{s}=8\mathrm{TeV}$. We observe an improvement of the perturbative convergence for the inclusive case and for the prediction with a jet veto upon the inclusion of the NNLO QCD corrections.

We give a detailed exposition of the formalism of kinetic field theory (KFT) with emphasis on the perturbative determination of observables. KFT is a statistical nonequilibrium classical field theory based on the path integral formulation of classical mechanics, employing the powerful techniques developed in the context of quantum field theory to describe classical systems. Unlike previous work on KFT, we perform the integration over the probability distribution of initial conditions in the very last step. This significantly improves the clarity of the perturbative treatment and allows for physical interpretation of intermediate results. We give an introduction to the general framework, but focus on the application to interacting $N$-body systems. Specializing the results to cosmic structure formation, we reproduce the linear growth of the cosmic density fluctuation power spectrum on all scales from microscopic, Newtonian particle dynamics alone.

We show how to compute classical wave observables using quantum scattering amplitudes. We discuss observables both with incoming and with outgoing waves. The required classical limits are naturally described by coherent states of massless bosons. We recompute the classic gravitational deflection of light, and also show how to rederive Thomson scattering. We introduce a new class of local observables, which includes the asymptotic electromagnetic and gravitational Newman-Penrose scalars. As an example, we compute a simple radiated waveform: the expectation of the electromagnetic field in charged-particle scattering. At leading order, the waveform is trivially related to the five-point scattering amplitude.

We determine the higher symmetries of 5D SCFTs engineered from M-theory on a ${\mathbb{C}}^3/\mathrm{\Gamma }$ background for $\mathrm{\Gamma }$ a finite subgroup of $SU(3)$. This resolves a longstanding question as to how to extract this data when the resulting singularity is nontoric (when $\mathrm{\Gamma }$ is non-Abelian) and/or not isolated (when the action of $\mathrm{\Gamma }$ has fixed loci). The Bogomol’nyi-Prasad-Sommerfield (BPS) states of the theory are encoded in a 1D quiver quantum mechanics gauge theory which determines the possible 1-form and 2-form symmetries. We also show that this same data can also be extracted by a direct computation of the corresponding defect group associated with the orbifold singularity. Both methods agree, and these computations do not rely on the existence of a resolution of the singularity. We also observe that when the geometry faithfully captures the global 0-form symmetry, the abelianization of $\mathrm{\Gamma }$ detects a 2-group structure (when present). As such, this establishes that all of this data is indeed intrinsic to the superconformal fixed point rather than being an emergent property of an IR gauge theory phase.

We discuss how small-scale density perturbations on the Fresnel scale affect amplitudes and phases of gravitational waves that are magnified by gravitational lensing in geometric optics. We derive equations that connect the small-scale density perturbations with the amplitude and phase fluctuations to show that such perturbative wave optics effects are significantly boosted in the presence of macro model magnifications such that amplitude and phase fluctuations can easily be observed for highly magnified gravitational waves. We discuss expected signals due to microlensing by stars, dark matter substructure, fuzzy dark matter, and primordial black holes.

We demonstrate that measurements of the neutral-current Drell-Yan transverse momentum distribution binned in invariant mass are sensitive to unexplored dimension-eight parameters of the Standard Model effective field theory (SMEFT). These distributions are sensitive to four-fermion operators with additional QCD field strength tensors. The determination of the Wilson coefficients of these operators provides a useful diagnostic tool that distinguishes possible ultraviolet completions of the SMEFT. We study how well these effects can be probed by current LHC data, and explore the sensitivity of the future high-luminosity LHC (HL-LHC) to these operators. We find that the HL-LHC data has the potential to strongly probe this sector of the SMEFT.

We propose a measure of quantum state complexity defined by minimizing the spread of the wave function over all choices of basis. Our measure is controlled by the “survival amplitude” for a state to remain unchanged, and can be efficiently computed in theories with discrete spectra. For continuous Hamiltonian evolution, it generalizes Krylov operator complexity to quantum states. We apply our methods to the harmonic and inverted oscillators, particles on group manifolds, the Schwarzian theory, the SYK model, and random matrix models. For time-evolved thermofield double states in chaotic systems our measure shows four regimes: a linear ramp up to a peak that is exponential in the entropy, followed by a slope down to a plateau. These regimes arise in the same physics producing the slope-dip-ramp-plateau structure of the spectral form factor. Specifically, the complexity slope arises from spectral rigidity, distinguishing different random matrix ensembles.

The Schur limit of the superconformal index of a four-dimensional $\mathcal{N}=2$ superconformal field theory encodes rich physical information about the protected spectrum of the theory. For a Lagrangian model, this limit of the index can be computed by a contour integral of a multivariate elliptic function. However, surprisingly, so far it has eluded exact evaluation in a closed, analytical form. In this paper we propose an elementary approach to bring to heel a large class of these integrals by exploiting the ellipticity of their integrand. Our results take the form of a finite sum of (products of) the well-studied flavored Eisenstein series. In particular, we derive a compact formula for the fully flavored Schur index of all theories of class $\mathcal{S}$ of type ${\mathfrak{a}}_1$, we put forward a conjecture for the unflavored Schur indices of all $\mathcal{N}=4$ super Yang-Mills theories with gauge group $SU(N)$, and we present closed-form expressions for the index of various other gauge theories of low ranks. We also discuss applications to non-Lagrangian theories, modular properties, and defect indices.

We consider the interplay of the early dark energy (EDE) model, the swampland distance conjecture (SDC), and cosmological parameter tensions. EDE is a proposed resolution of the Hubble tension relying upon a near-Planckian scalar field excursion, while the SDC predicts an exponential sensitivity of masses of other fields to such an excursion, $m\propto e^{-c|\mathrm{\Delta }\varphi |/M_{\mathrm{pl}}}$ with $c\sim \mathcal{O}(1)$. Meanwhile, EDE is in tension with large-scale structure (LSS) data, due to shifts in the standard $\mathrm{\Lambda }$ cold dark matter parameters necessary to fit the cosmic microwave background. One might hope that a proper treatment of the model, e.g., accounting for the SDC, may ameliorate the tension with LSSs. Motivated by these considerations, we introduce the early dark sector (EDS) model, wherein the mass of dark matter is exponentially sensitive to super-Planckian field excursions of the EDE scalar. The EDS model exhibits new phenomenology in both the early and late Universe, the latter due to an EDE-mediated dark matter self-interaction, which manifests as an enhanced gravitational constant on small scales. This EDE-induced dark-matter-philic “fifth force,” while constrained to be small, remains active in the late Universe and is not screened in virialized halos. We find that the new interaction with dark matter partially resolves the LSS tension. However, the marginalized posteriors are nonetheless consistent with $f_{\mathrm{EDE}}=0$ at 95% CL once the Dark Energy Survey year 3 measurement of $S_8$ is included. We additionally study constraints on the model from Atacama Cosmology Telescope data and find a factor of 2 improvement on the error bar on the SDC parameter $c$, along with an increased preference for the EDE component. We discuss the implications of these constraints for the SDC and find the tightest observational constraints to date on a swampland parameter, suggesting that an EDE description of cosmological data is in tension with the SDC.

The Galileon scalar field theory is a prototypical example of an effective field theory that exhibits the Vainshtein screening mechanism, which is incorporated into many extensions to Einstein gravity. The Galileon describes the helicity-zero mode of gravitational radiation, the presence of which has significant implications for predictions of gravitational waves from orbiting objects and for tests of gravity sensitive to additional polarizations. Because of the derivative nature of their interactions, Galileons are superficially not well posed as effective field theories. Although this property is properly understood merely as an artifact of the effective field theory truncation, and is not theoretically worrisome, at the practical level it nevertheless renders numerical simulation highly problematic. Notwithstanding, previous numerical approaches have successfully evolved the system for reasonable initial data by slowly turning on the interactions. We present here two alternative approaches to improving numerical stability in Galileon numerical simulations. One of these is a minor modification of previous approaches, which introduces a low-pass filter that amounts to imposing a UV cutoff together with a relaxation method of turning on interactions. The second approach amounts to constructing a (numerical) UV completion for which the dynamics of the high momentum modes is under control and for which it is unnecessary to slowly turn on nonlinear interactions. We show that numerical simulations of the UV theory successfully reproduce the correct Galileon dynamics at low energies, consistent with the low-pass filter method and with previous numerical simulations.

We report the detection of ten new binary black hole (BBH) mergers in the publicly released data from the first half of the third observing run (O3a) of advanced LIGO and advanced Virgo. We identify candidates using an updated version of the search pipeline described in Venumadhav et al. [Phys. Rev. D 100, 023011 (2019)] (the “IAS pipeline” [T. Venumadhav et al., Phys. Rev. D 101, 083030 (2020).]) and compile a catalog of signals that pass a significance threshold of astrophysical probability greater than 0.5 (following the GWTC-2.1 [R. Abbott et al. (The LIGO Scientific Collaboration, the Virgo Collaboration), arXiv:2108.01045.] and 3-OGC [A. H. Nitz et al., Astrophys. J. 922, 76 (2021).] catalogs). The updated IAS pipeline is sensitive to a larger region of parameter space, applies a template prior that accounts for different search volume as a function of intrinsic parameters, and uses an improved coherent detection statistic that optimally combines the data from the Hanford and Livingston detectors. Among the ten new events, we observe interesting astrophysical scenarios including sources with confidently large effective spin parameters in both the positive and negative directions, high-mass black holes that are difficult to form in stellar collapse models due to (pulsational) pair instability, and low-mass mergers that bridge the gap between neutron stars and the lightest observed black holes. We infer source parameters in the upper and lower black hole mass gaps with both extreme and near-unity mass ratios, and one of the possible neutron star–black hole (NSBH) mergers is well localized for electromagnetic (EM) counterpart searches. We detect all of the GWTC-2.1 BBH mergers with coincident data in Hanford and Livingston except for three loud events that get vetoed, which is compatible with the false-positive rate of our veto procedure, and three that fall below the detection threshold. We also return to significance the event GW190909_114149, which was reduced to a subthreshold trigger after its initial appearance in GWTC-2 [R. Abbott et al., Phys. Rev. X 11, 021053 (2021).]. This amounts to a total of 42 BBH mergers detected by our pipeline’s search of the coincident Hanford-Livingston O3a data.

The Migdal effect inside detectors provides a new possibility of probing the sub-GeV dark matter (DM) particles. While there has been well-established methods treating the Migdal effect in isolated atoms, a coherent and complete description of the valence electrons in a semiconductor is still absent. The bremstrahlunglike approach is a promising attempt, but it turns invalid for DM masses below a few tens of MeV. In this paper, we lay out a framework where phonon is chosen as an effective degree of freedom to describe the Migdal effect in semiconductors. In this picture, a valence electron is excited to the conduction state via exchange of a virtual phonon, accompanied by a multiphonon process triggered by an incident DM particle. Under the incoherent approximation, it turns out that this approach can effectively push the sensitivities of the semiconductor targets further down to the MeV DM mass region.

We present new ${\nu }_{\mu }\to {\nu }_e$, ${\nu }_{\mu }\to {\nu }_{\mu }$, ${\overline{\nu }}_{\mu }\to {\overline{\nu }}_e$, and ${\overline{\nu }}_{\mu }\to {\overline{\nu }}_{\mu }$ oscillation measurements by the NOvA experiment, with a 50% increase in neutrino-mode beam exposure over the previously reported results. The additional data, combined with previously published neutrino and antineutrino data, are all analyzed using improved techniques and simulations. A joint fit to the ${\nu }_e$, ${\nu }_{\mu }$, ${\overline{\nu }}_e$, and ${\overline{\nu }}_{\mu }$ candidate samples within the 3-flavor neutrino oscillation framework continues to yield a best-fit point in the normal mass ordering and the upper octant of the ${\theta }_{23}$ mixing angle, with $\mathrm{\Delta }{m}_{32}^2=(2.41\pm 0.07)\times {10}^{-3}{\mathrm{eV}}^2$ and ${\sin }^2{\theta }_{23}=0.57_{-0.04}^{+0.03}$. The data disfavor combinations of oscillation parameters that give rise to a large asymmetry in the rates of ${\nu }_e$ and ${\overline{\nu }}_e$ appearance. This includes values of the charge parity symmetry (CP) violating phase in the vicinity of ${\delta }_{\mathrm{CP}}=\pi /2$ which are excluded by $>3\sigma$ for the inverted mass ordering, and values around ${\delta }_{\mathrm{CP}}=3\pi /2$ in the normal ordering which are disfavored at $2\sigma$ confidence.

The analytic structure of non-Gaussian correlators in inflationary cosmologies has recently been proposed as a test of the quantum origin of structure in the Universe. To further understand this proposal, we explore the analogous equal-time in-in correlators in flat space and show they exhibit the same features as their cosmological counterparts. The quantum vacuum is uniquely identified by in-in correlators with a total energy pole and no additional poles at physical momenta. We tie this behavior directly to the S-matrix and show that poles at physical momenta always arise from scattering of particles present in the initial state. We relate these flat-space in-in correlators to the probability amplitude for exciting multiple Unruh-de Witt detectors. Localizing the detectors in spacetime, through the uncertainty principle, provides the energy and momentum needed to excite the vacuum and explains the connection to cosmological particle production. In addition, the entanglement of these detectors provides a probe of the entangled state of the underlying field and connects the properties of the correlators to the range of entanglement of the detectors.

High-energy photons with $\mathcal{O}(\mathrm{MeV})$ energies from radioactive contaminants can scatter in a solid-state target material and constitute an important low-energy background for sub-GeV dark matter direct-detection searches. This background is most noticeable for energy deposits in the 1–100 meV range due to the partially coherent scattering enhancement in the forward scattering direction. We comprehensively quantify the resulting single- and multiphonon background in Si, Ge, GaAs, SiC, and ${\mathrm{Al}}_2{\mathrm{O}}_3$ target materials, which are representative of target materials of interest in low-mass dark matter searches. We use a realistic representation of the high-energy photon background, and contrast the expected background phonon spectrum with the expected dark matter signal phonon spectrum. An active veto is needed to suppress this background sufficiently in order to allow for the detection of a dark matter signal, even in well-shielded environments. For comparison we also show the expected single- and multiphonon event rates from coherent neutrino-nucleus scattering due to solar neutrinos, and find that they are subdominant to the photon-induced phonon background.

Superradiant instabilities may create clouds of ultralight bosons around rotating black holes, forming so-called “gravitational atoms“. It was recently shown that the presence of a binary companion can induce resonant transitions between bound states of these clouds, whose backreaction on the binary’s orbit leads to characteristic signatures in the emitted gravitational waves. In this work, we show that the interaction with the companion can also trigger transitions from bound to unbound states of the cloud—a process that we refer to as “ionization” in analogy with the photoelectric effect in atomic physics. The orbital energy lost in the process overwhelms the losses due to gravitational wave emission and contains sharp features carrying information about the energy spectrum of the cloud. Moreover, we also show that if the companion is a black hole, then the part of the cloud impinging on the event horizon will be absorbed. This “accretion” leads to a significant increase of the companion’s mass, which alters the dynamical evolution and ensuing waveform of the binary. We argue that a combined treatment of resonances, ionization, and accretion is crucial to discover and characterize gravitational atoms with upcoming gravitational-wave detectors.

For any quantum system invariant under gauging a higher-form global symmetry, we construct a noninvertible topological defect by gauging in only half of the spacetime. This generalizes the Kramers-Wannier duality line in $1+1$ dimensions to higher spacetime dimensions. We focus on the case of a one-form symmetry in $3+1$ dimensions, and determine the fusion rule. From a direct analysis of one-form symmetry protected topological phases, we show that the existence of certain kinds of duality defects is intrinsically incompatible with a trivially gapped phase. We give an explicit realization of this duality defect in the free Maxwell theory, both in the continuum and in a modified Villain lattice model. The duality defect is realized by a Chern-Simons coupling between the gauge fields from the two sides. We further construct the duality defect in non-Abelian gauge theories and the ${\mathbb{Z}}_N$ lattice gauge theory.

Self-gravitating bodies can have an arbitrarily complex shape, which implies a much richer multipolar structure than that of a black hole in general relativity. With this motivation, we study the corrections to the dynamics of a binary system due to generic, nonaxisymmetric mass quadrupole moments to leading post-Newtonian (PN) order. Utilizing the method of osculating orbits and a multiple scale analysis, we find analytic solutions to the precession and orbital dynamics of a (generically eccentric) binary in terms of the dimensionless modulus parameters ${\epsilon }_m$, corresponding to axial $m=1$ and polar $m=2$ corrections from oblateness/prolateness. The solutions to the precession dynamics are exact for $0\le {\epsilon }_2<1$, and perturbative in ${\epsilon }_1\ll 1$. We further compute the leading order corrections to the gravitational wave amplitude and phase for a quasicircular binary due to mass quadrupole effects. Making use of the stationary phase approximation and shifted uniform asymptotics (SUA), the corrections to the phase enter at relative 2PN order, while the amplitude modulations enter at $-0.5\mathrm{PN}$ order with a SUA amplitude correction at 3.25PN order, relative 2PN order to the leading order SUA correction. By investigating the dephasing due to generic quadrupole moments, we find that a phase difference $\gtrsim 0.1$ radians is achievable for ${\epsilon }_m\gtrsim {10}^{-3}$, which suggests that constraints with current and future ground-based gravitational wave detectors are possible. Our results can be implemented in parameter estimation studies to constrain generic multipolar deformations of the Kerr geometry and of neutron stars.

We report a search for an anomalous excess of inclusive charged-current (CC) ${\nu }_e$ interactions using the Wire-Cell event reconstruction package in the MicroBooNE experiment, which is motivated by the previous observation of a low-energy excess (LEE) of electromagnetic events from the MiniBooNE experiment. With a single liquid argon time projection chamber detector, the measurements of ${\nu }_{\mu }$ CC interactions as well as ${\pi }^0$ interactions are used to constrain signal and background predictions of ${\nu }_e$ CC interactions. A data set collected from February 2016 to July 2018 corresponding to an exposure of $6.369\times {10}^{20}$ protons on target from the Booster Neutrino Beam at FNAL is analyzed. With $x$ representing an overall normalization factor and referred to as the LEE strength parameter, we select 56 fully contained ${\nu }_e$ CC candidates while expecting $69.6\pm 8.0$ (stat.) $\pm 5.0$ (sys.) and $103.8\pm 9.0$ (stat.) $\pm 7.4$ (sys.) candidates after constraints for the absence (${\mathrm{eLEE}}_{x=0}$) of the median signal strength derived from the MiniBooNE observation and the presence (${\mathrm{eLEE}}_{x=1}$) of that signal strength, respectively. Under a nested hypothesis test using both rate and shape information in all available channels, the best-fit $x$ is determined to be 0 (${\mathrm{eLEE}}_{x=0}$) with a 95.5% confidence level upper limit of $x$ at 0.502. Under a simple-vs-simple hypotheses test, the ${\mathrm{eLEE}}_{x=1}$ hypothesis is rejected at $3.75\sigma$, while the ${\mathrm{eLEE}}_{x=0}$ hypothesis is shown to be consistent with the observation at $0.45\sigma$. In the context of the eLEE model, the estimated 68.3% confidence interval of the ${\nu }_e$ CC hypothesis to explain the LEE observed in the MiniBooNE experiment is disfavored at a significance level of more than $2.6\sigma$ ($3.0\sigma$) considering MiniBooNE’s full (statistical) uncertainties.

This article presents a measurement of ${\nu }_e$ interactions without pions in the final state using the MicroBooNE experiment and an investigation into the excess of low-energy electromagnetic events observed by the MiniBooNE Collaboration. The measurement is performed in exclusive channels with ($1e\mathrm{N}p0\pi$) and without ($1e0p0\pi$) visible final-state protons using $6.86\times {10}^{20}$ protons on target of data collected from the Booster Neutrino Beam at Fermilab. Events are reconstructed with the Pandora pattern recognition toolkit and selected using additional topological information from the MicroBooNE liquid argon time projection chamber. Using a goodness-of-fit test, the data are found to be consistent with the predicted number of events with nominal flux and interaction models with a $p$ value of 0.098 in the two channels combined. A model based on the low-energy excess observed in MiniBooNE is introduced to quantify the strength of a possible ${\nu }_e$ excess. The analysis suggests that, if an excess is present, it is not consistent with a scaling of the ${\nu }_e$ contribution to the flux as predicted by the signal model used in the analysis. Combined, the $1e\mathrm{N}p0\pi$ and $1e0p0\pi$ channels do not give a conclusive indication about the tested model, but separately, they both disfavor the low-energy excess model at $>90\%\mathrm{C}.\mathrm{L}.$ The observation in the most sensitive $1e\mathrm{N}p0\pi$ channel is below the prediction and consistent with no excess. In the less sensitive $1e0p0\pi$ channel, the observation at low energy is above the prediction, while overall there is agreement over the full energy spectrum.